fact verification
**Fact verification** is the **process of checking claims against trusted evidence to determine whether statements are supported, contradicted, or unresolved** - verification is a central safety control for AI systems that generate natural language answers.
**What Is Fact verification?**
- **Definition**: Evidence-based validation workflow for factual claims in model outputs.
- **Verification States**: Common outcomes are supported, refuted, or insufficient evidence.
- **Evidence Sources**: Uses high-trust documents, structured databases, and timestamped records.
- **Pipeline Location**: Runs before answer finalization or as a post-generation guardrail.
**Why Fact verification Matters**
- **Hallucination Control**: Reduces incorrect claims that damage reliability and safety.
- **Compliance Assurance**: High-stakes domains need defensible evidence for every critical statement.
- **User Trust**: Verified answers with citations are easier for users to accept.
- **Incident Prevention**: Early detection of factual errors prevents downstream operational mistakes.
- **Model Governance**: Verification traces support audits and continuous model improvement.
**How It Is Used in Practice**
- **Claim Extraction**: Split generated responses into atomic checkable statements.
- **Evidence Matching**: Retrieve and score supporting or contradicting passages per claim.
- **Decision Policy**: Block or flag responses when verification confidence is below threshold.
Fact verification is **a mandatory guardrail for trustworthy AI answer systems** - robust fact checking converts retrieval evidence into verifiable response quality.